Control of permanent magnet AC servo motors without absolute rotor position transducers

An attempt to control permanent magnet AC servo motors without the detection of the rotor position by absolute position transducers such as absolute encoders or resolvers is presented. The incremental encoder has been used in order to obtain the information of the rotor position and speed. A feedforward controller and an acceleration feedback controller are incorporated into the conventional PI controller in order to obtain high dynamic performance of AC servo motors. The proposed control scheme has been implemented on a control system based on a digital signal processor (DSP). Experimental results show that the proposed control system can be effectively applied to AC servo motors in order to obtain high dynamic performance